Various types of calculations (e.g., financial calculations) require multiple items of input data. A net present value calculation, for example, requires the cash flow values for each period and an investment interest rate as input values on which to base the calculation. A user will be troubled if the user wants to perform such a calculation but does not know how to provide the various input data values into the calculator. The user interface for a calculator is typically quite limited and often not helpful enough to many users.